title: Effect of a westward transmeridian flight on ambulatory blood pressure monitoring in normotensive subjects.
abstract: OBJECTIVE
  To evaluate the effects of a westward transmeridian flight over six time zones (from Milan to New York) on ambulatory blood pressure monitoring (ABPM) in normotensive individuals.
  
  
  METHODS
  Eighteen normotensive subjects (blood pressure < 140/90 mmHg), 11 men and seven women, of mean age 38.3 years, were studied. On the day of travel they underwent 26 h noninvasive ABPM (started at 1100 h); the take-off time was 1200 h and the landing time was 8 h later, at 1400 h New York time (2000 h Italian time). Subjects were requested not to sleep until 2300 h and to get up at 0700 h the following morning. The results were compared with those of a 26 h ABPM performed in Italy the week before during which they slept from 2300 h to 0700 h.
  
  
  RESULTS
  During the flight blood pressure and heart rate did not change compared with values during the corresponding time interval of the control day. After the landing, during the New York afternoon and evening (corresponding to the Italian sleeping time), blood pressure and heart rate remained unchanged, whereas during the night they decreased significantly, although their drop was less pronounced than that during the control day.
  
  
  CONCLUSIONS
  The results of this study indicate that the decrease in blood pressure during sleep is the result of sleep itself rather than of the actual time of day.
authors.affiliation: Department of Internal Medicine and Therapeutics, University of Pavia, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Fogari
authors.forename: P
authors.initials: P
authors.lastname: Lusardi
authors.forename: A
authors.initials: A
authors.lastname: Zoppi
authors.forename: M
authors.initials: M
authors.lastname: Pasotti
authors.forename: L
authors.initials: L
authors.lastname: Corradi
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D012890:Sleep / Q000502:physiology*